I want to have the last few blog posts show on my home page but I don’t want the entire post, just a small preview (including image). I currently have it set up to have the post title and preview image, but is there a way to include the first 50 words of the post below the photo and title of the post?

You can do something close, but not quite exactly. If you use the three column setup like you have now, and do a post from category for each (with different categories). Then select “Preview Image and post content”. The content preview will be determined by the “More” tag within the post. You can insert it in your posts to customize where the preview stops without effecting the article.

The more tag is located in the visual editor’s top bar, in between the Links and the Spellchecker. You can also insert it with Alt+Shift+T.